The score was tied at 3, when Prince Fielder led off the 11th with a double into the left-field corner. Three batters later, pinch-hitter Gabe Kapler drove him in with a single, giving the Brewers a lead they wouldn't relinquish.
"I was trying to throw a slider back-door, but I left it right in the zone, and he got me," Rivera said of Fielder's double. "He made an adjustment, and he got me."
Rivera also said he tried to come with an inside fastball on Kapler, but it didn't work out.
"You have to have a short-term memory and get ready for tomorrow," the reliever added.
Bergmann continued his stellar work since being recalled from Triple-A Columbus on May 14. The right-hander struck out eight batters over 5 2/3 innings and extended his streak of scoreless innings to 19 2/3. He has 22 strikeouts over that stretch.
Bergmann said after the game that confidence in his fastball, curveball and slider have made him a better pitcher than even last year, when he almost no-hit the Braves.
"I think my curveball is a lot better than it's been at any time in the past at the Major League level," Bergmann said. "So when I'm able to throw a curveball, it gives me three pitches I'm confident in. I'm still bringing along the changeup."
Bergmann said the ability to throw any of those pitches at any time also has made him a better pitcher.
"Being able to throw any of those three pitches for strikes in almost any count is really an asset for me," he said, adding that catcher Jesus Flores' confidence to call any pitch any time makes it easier to throw off hitters.
Nationals manager Manny Acta acknowledged Bergmann's good outings of late, calling him "tremendous" since his Major League return. Acta said Bergmann's ability to locate his pitches has been the key.
"He did the same thing he's done in the other outings, and just gave us a very good chance to win the ballgame today," Acta said.
The Nationals staked Bergmann to an early lead when Cristian Guzman took a first-inning 1-1 pitch over the right-field wall against Ben Sheets for his fifth home run of the season. Washington put another run up an inning later, when Flores knocked in Elijah Dukes with a double.
But the Brewers took advantage of some timely hitting and a Dmitri Young error in the seventh inning to tie the game at 2 against relievers Charlie Manning and Brian Sanches. Milwaukee picked up its third run in the top of the eighth, when Mike Cameron walked, stole second and scored on Fielder's sacrifice fly two batters later.
With two outs in the bottom of the eighth inning, Young took an 0-1 pitch from Brewers left-hander Brian Shouse to the top of the left-center-field wall. The play initially was ruled a triple, but the umpires met after Acta came out to argue. The umps then broke their huddle and awarded Young his first home run of the year.
The Brewers bullpen locked Washington down late, allowing only Young's homer over five innings. Carlos Villanueva was Milwaukee's top arm out of the 'pen, striking out five over two innings and picking up the win.
The Nationals saw solid defensive play from their outfield Monday, particularly from Dukes and Lastings Milledge. The latter made a sliding catch in center field early in the game, and Dukes threw out Fielder in the second trying to stretch a liner off the wall from a single to a double.
"We played pretty much everybody straight up," Milledge said. "We knew they like to drive the ball straightaway."
Acta rested some of his starters after the day game Sunday and a West Coast road trip on tap, but several players still found their way off the bench because of extra innings. After the game, Acta described the extra playing time as "no big deal," and credited his players for "battling" all game.
"We played them tough. I'm proud of these guys. I'm proud of my pitching staff," Acta said. "When our offense shows up, things obviously will be easier for us."
Zachary Osterman is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.